A widowed friend of ours is still keeping her husband’s Facebook account open, several months after he passed away. She has no plans to close it. Many experts suggest “memorializing” such an account to make it impossible to send messages there, but she sees no reason to do this either. We agree. Survivors probably want to hear from anyone who hasn’t yet learned of the death of their friend so it’s best to keep channels open.

We recently explained what they call a “hashtag” on Twitter: It looks like this: “#.” It’s used to organize and navigate your way around Twitter. Typing #BillGates when you’re logged into Twitter, for example, takes you to Gates’ Twitter page. A reader wrote in to say he loved the explanation, but what about the “@” on Twitter?

If you’re one of the 271 million Twitter users, you may want to know how many people are potentially viewing your tweets. Go to Analytics.Twitter.com to find out. We found that our tweets were received daily by around 1800 people. Of course, just because someone is getting your tweets doesn’t mean they’re actually reading them. Stop us before we tweet again!

Many people tell us they’re confused by Twitter. What is it? Who’s out there? And what are they saying? Oh: And why would we care? Twitter delivers “tweets.” And each “tweet” is no more than 140 characters. But there’s usually a link in there to a longer story. Tweets can come in to your computer, your phone, or whatever you have that can connect to the Internet. You can get pages of tweets from sources and subjects you select and they can range from bits of chit-chat about family members to what’s happening in the Congo. Surprisingly often the source of those tweets may be from someone right on the spot, perhaps snapping a picture long before a reporter gets […]

Remind101 — After a high school principal reminded us of the text messaging app “Group Me,” a teacher wrote with another suggestion: “Remind101.” This is free from Remind101.com and lets you send text messages to any group. They can’t reply. He just wanted to notify parents and teachers of events; he doesn’t really want to hear back.

SnapChat became famous for photo messages that quickly disappear after they’re viewed. Now they’ve added video messages that disappear. So you can take as many dumb pictures as you want and at least they won’t be saved.

A high school principal wrote to ask us what’s the best way to send text messages to a group. Before we could answer, he wrote back to say he’d tried “GroupMe,” and unfortunately woke up a bunch of teachers in the middle of the night. (Those teachers should have adjusted their settings to turn off the message alert. You don’t have to get a ding every time a message comes in.)

Just as it sounds, GroupMe works on the computer or phone to send text messages to groups. If you have a person’s cell phone number, they don’t need to have the app installed. If you only have their email address, they’ll get an invitation to install the app.